Therapy Never Initiated, Discontinued Early by Some
Breast Cancer Patients

Ann Arbor, MI—Concerned about side-effects, one-quarter of women either do not start or do not complete the 5-year course of hormone-blocking therapies as part of their breast cancer treatment, according to
a study from the University of Michigan Comprehensive Cancer Center.

A 5-year course of therapy of daily tamoxifen or aromatase inhibitors is recommended for women whose breast cancer is found to express the hormones estrogen or progesterone. Not only have the drugs been shown to reduce cancer recurrence and increase survival, but recent studies have suggested there may be even more benefit for some women to continue the therapy for 10 years.

Yet, the study of 743 women eligible for endocrine therapy, published online by the journal Breast Cancer Research and Treatment, found that 11% never began the treatments and 15% ended the therapy early.

“We're doing well with women taking endocrine therapy, but there's work to do,” said
lead study author Christopher Friese, PhD, RN. “If guidelines begin to shift so that some women at high risk of breast cancer recurring need 10 years of endocrine therapy, then the number of women who persist with treatment will likely worsen. We need to develop better ways of supporting women through this therapy.”

Menopause-like side effects, such as hot flashes or vaginal dryness, were the most common reason for patients to either never initiate or discontinue endocrine therapy. Both types of the drugs, but particularly aromatase inhibitors, can also cause joint pain, according to information in the article.

Researchers focused on a group of women in the Detroit and Los Angeles areas who were diagnosed with breast cancer and reported to Surveillance, Epidemiology and End Results, or SEER, tumor registries. Surveys of the women were conducted at about 9 months after their diagnosis and again about four years later, with questions about their use of tamoxifen or any type of aromatase inhibitor.

The study found that women who expressed more worry about cancer recurrence and women who already were on regular medications were more likely to complete the endocrine therapy. Less likely to begin therapy were women who reported receiving inadequate information about endocrine therapy, as were women being treated in follow-up by a breast surgeon as opposed to those seeing a medical oncologist.

The authors called for more pharmacists and other health professionals to offer more education to “reassure and motivate” patients to initiate and continue therapy.

“Enhanced patient education about potential side effects and the effectiveness of adjuvant endocrine therapy in improving outcomes may improve initiation and persistence rates and optimize breast cancer survival,” they added.